Heat the oil in a large pot over medium-high heat. Add the carrots, celery, onion, and garlic. Cook until tender, stirring occasionally, about 8 minutes.
Add the cabbage, broth, tomatoes, thyme, salt, and pepper. Bring to a boil.
Cover, reduce the heat to medium-low, and simmer until the cabbage is tender, about 25 minutes. Sprinkle with chopped parsley before serving. The soup can be stored in airtight containers in the fridge for up to 1 week or frozen for up to 6 months.
Notes
For a hearty cabbage soup: The recipe, as written, yields a lighter vegetable soup. To make a soup that’s more satiating, add 2 chopped potatoes to the pot along with the chopped cabbage. You could also add cooked rice or cooked orzo in the last few minutes of cooking.
For extra protein: If you’d prefer to try this recipe for cabbage soup with meat, cooked meats like shredded chicken breast, pulled pork, or browned ground beef or turkey are delicious ways to up the protein of this soup. If you’d rather keep the soup meatless, opt for rinsed and drained canned white beans, kidney beans, or chickpeas. Simply add these in the last 5 or so minutes of cooking time to heat through.
Use up extra veggies: If you have vegetables lurking in your refrigerator, this soup is the perfect way to use them up. Green beans, peas, bell pepper, or leafy greens such as spinach or kale are all excellent additions.
For a subtle heat, add red pepper flakes to taste.
Use fresh herbs: You can use 1½ tablespoons of chopped fresh thyme instead of dried thyme. Or substitute it with other herbs like basil, oregano, or rosemary.